Table 4.
Results Estimated by the 2SLS and CMP Methods.
| 2SLS | CMP | |||
|---|---|---|---|---|
| Stage I | Stage II | Stage I | Stage II | |
| Internet | −2.9012*** | −0.3774*** | ||
| (1.0356) | (0.1139) | |||
| Internet penetration rate of the | 0.4584*** | 3.9455*** | ||
| county level | (0.0367) | (0.1557) | ||
| DWH | 6.4938 | |||
| atanhrho_12 | 0.1745*** | |||
| (0.0632) | ||||
| Covariates | Yes | Yes | No | Yes |
| Province dummies | Yes | Yes | No | Yes |
| N | 7,617 | 7,617 | ||
***, **, and *
indicate significance at 1, 5, and 10%, respectively. Standard errors are presented in parentheses. DWH is the estimated parameter of Durbin–Wu–Hausman test. The atanhro_12 is a parameter in the CMP model. If it is different from zero, then there are unobserved factors simultaneously affecting the dependent variable and main independent variable, suggesting the main independent variable is endogenous.